(1) Field of the Invention
The present invention relates to cured epoxy resin and polyglycoside-based cured polymers and to a process and compositions for the preparation of these polymers. In particular, the present invention relates to the curing of epoxy resin precursors with a polyglycoside based polymer. The polymers can contain fillers of various known types, preferably those which are natural. The polyglycoside moiety provides a degree of biogradability to the resulting polymer not usually available in epoxy resin based polymers. The polymers are stable to elevated temperatures up to 300xc2x0 C., and thus are useful in vehicle engine compartments for sound deadening and the like.
(2) Description of Related Art
Recently, there has been increasing interest in the use of biocomposites of natural fibers, particularly cellulosic fibers, especially in the automobile industry. These composites are reported to offer advantages of xcx9c20% reduction in processing temperature and xcx9c25% reduction in cycle time in addition to a weight reduction of about xcx9c30% over conventional glass fiber composites (Saheb, D. N., et al., Advances in Polymer Technology 18 4 351 (1999)). For automotive applications biocomposites have to meet several demanding requirements such as temperature resistance and wet environmental resistance (Reussmann, T., et al., Advanced Engineering Materials 1, 2, 140 (1999)). The incorporation of biobased polymer with natural fibers would be the best combination for development of environmentally friendly composites if the developed biocomposites meet the demanding requirements.
Glucose maleic acid ester vinyl copolymer (GMAEVC) has been developed to use as a biodegradable adhesive for the paper and packaging industry. GMAEVC contains reactive carboxylic and hydroxyl functional groups in its structure. This leads to cost effective and better performing of biocomposites.
U.S. Pat. Nos. 5,869,173 and 6,171,688 to Zheng to al show composites which can be formed.
It is therefore an object of the present invention to provide novel epoxy resin and polyglycoside based polymers. Further, it is an object of the present invention to provide such polymers which have a degree of biodegradability and high temperature resistance. These and other objects will become increasingly apparent by reference to the following description and the Figures.
The present invention relates to a curable polymer composition which comprises:
(a) an epoxy resin precursor; and
(b) a co-polymer of a polyglycoside acid or acid ester reacted with an organic anhydride or acid, and optionally with a vinyl monomer, wherein the ratio of (a) to (b) produces a cured polymer composition.
In particular the present invention relates to a curable polymer composition which comprises:
(a) an epoxy resin precursor; and
(b) a copolymer of a polyglycoside acid or acid ester of the formula II or III as follows: 
and mixtures thereof and optionally a vinyl monomer, wherein R and Rxe2x80x3 are alkyl containing 1 to 30 carbon atoms and wherein the ratio of (a) to (b) produces a cured polymer composition. X and y are integers between 0 and 4 but x and y are not O at the same time.
The present invention particularly relates to a curable polymer composition which comprises:
(a) liquid epoxy resin; and
(b) a copolymer of the formula as follows: 
wherein Glu is a saccharide moiety which is derived from a sugar selected from the group consisting of xcex1-D-glucose, fructose, mannose, galactose, talose, gulose, allose, altrose, idose, arabinose, xylose, lyxosc, ribose, and mixtures thereof, or by hydrolysis of a material selected from the group consisting of starch, corn syrups, maltodextrins, maltose, sucrose, lactose, maltotriose, xylobiose, mellibiose, cellobiose, raffinose, stachiose, levoglucosan, 1,6-anhydroglucofuranose, and mixtures thereof, and wherein the ratio of (a) to (b) produces a cured polymer composition, wherein R1 and R2 are substituent groups of a vinyl monomer or mixture of vinyl monomers, wherein said vinyl monomer or mixture of vinyl monomers is selected from the group consisting of vinyl acetate, ethyl hexyl acrylate, butyl acrylate, ethyl acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, lauryl acrylate, methyl methacrylate, methacryclic acid, acrylic acid, other acrylates, mixtures of different acrylate monomers, ethylene, 1,3-butadiene, styrene, vinyl chloride, vinylpyrrolidinone, other vinyl monomers, and mixtures thereof, R is selected from the group consisting of a C1 to C30 alkyl and mixtures thereof, Rxe2x80x3 is selected from the group consisting of a C1 to C30 alkyl and mixtures thereof, or a hydrogen, n is an integer ranging from 0 to 10; x and y are integers ranging from 0 to 4, but not x and y are 0 at the same time, p and q are integers ranging from 0 to 1000, but not both p and q are zero, and wherein xcx9cxcx9cxcx9c indicates continuing polymer chains.
Preferably Glu is an xcex1-D-glucose moiety. Preferably the molar ratio of (a) to (b) is about 1:1. Preferably an alkyl polyglycoside is reacted with malic anhydride to form the polymer which is reacted with the vinyl monomer to form the copolymer. Preferably R1 and R2 and Rxe2x80x3 are selected from the group consisting of hydrogen and n-butyl.
The composition includes a filler. A fiber, particularly a cellulosic fiber, is preferred. Clay can be used as a filler. The compositions are cured to solid resins with or without the fillers.
The present invention also relates to a process for forming a cured polymer composition which comprises:
(a) providing a mixture of (1) a liquid mixture of an epoxy resin precursor and (2) a polyglucoside-organic anhydride reaction product which has optionally been polymerized with a vinyl monomer, wherein the ratio of (1) to (2) provides the cured polymer composition; and
(b) heating the mixture to produce the cured polymer.
In particular the present invention relates to a process for forming a cured polymer composition which comprises:
(a) providing (1) a liquid epoxy resin precursor and (2) a liquid copolymer of a polyglycoside acid or acid ester of the formula II or II as follows: 
and mixtures thereof which has optionally been reacted with a vinyl monomer wherein R and R11 are alkyl contain 1 to 30 carbon atoms, x and y are integers between 0 and 4 but not x and y are o at the same time and wherein the ratio of (1) to (2) produces the cured polymer composition; and
(b) heating the mixture to produce the cured polymer composition.
Further, the present invention relates to a process for the preparation of a cured polymer composition which comprises:
(a) providing a mixture of
(1) a liquid epoxy resin; and
(2) a liquid copolymer of the formula I as follows: 
wherein Glu is a saccharide moiety which is derived from a sugar from the group consisting of xcex1-D-glucose, fructose, mannose, galactose, talose, gulose, allose, altrose, idose, arabinose, xylose, lyxosc, ribose, and mixtures thereof, or by hydrolysis of a material selected from the group consisting of starch, corn syrups, maltodextrins, maltose, sucrose, lactose, maltotriose, xylobiose, mellibiose, cellobiose, raffinose, stachiose, levoglucosan, 1,6-anhydroglucofuranose, and mixtures thereof, wherein R1 and R2 are substituent groups of a vinyl monomer or mixture of vinyl monomers, wherein said vinyl monomer or mixture of vinyl monomers is selected from the group consisting of vinyl acetate, ethyl hexyl acrylate, butyl acrylate, ethyl acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, lauryl acrylate, methyl methacrylate, methacryclic acid, acrylic acid, other acrylates, mixtures of different acrylate monomers, ethylene, 1,3-butadiene, styrene, vinyl chloride, vinylpyrrolidinone other vinyl monomers, and mixtures thereof, R is selected from the group consisting of a C1 to C30 alkyl and mixtures thereof, Rxe2x80x3 is selected from the group consisting of a C1 to C30 alkyl and mixtures thereof, or a hydrogen, n is an integer ranging from 0 to 10; x and y are integers ranging from 0 to 4, but not x and y are 0 at the same time, p and q are integers ranging from 0 to 1000, but not both p and q are zero, and wherein xcx9cxcx9cxcx9c indcates continuing polymer chains, and wherein the ratio of (1) to (2) produces a cured polymer composition; and
(b) heating the mixture to produce the cured polymer composition.
Preferably R1, R2 and Rxe2x80x3 are selected from the group consisting of hydrogen and n-butyl. The epoxy resin precursor is preferably derived from the diglycidyl ether of bisphenol A. Preferably the epoxy resin precursor is derived from the diglycidyl ether of bisphenol A.
A xe2x80x9cGlycosidexe2x80x9d is a compound of a sugar with another substance, wherein sugar hydrolyzes to its constituents: glucosides yield glucose, fructosides yield fructose, galactosides yield galactose, and the like.
A xe2x80x9cpolyglycosidexe2x80x9d is a polymerized glycoside wherein multiple sugars are joined together and then connected to another organic group.
The present invention particularly relates to an environmentally friendly biocomposites polymer matrix composed of glucose based copolymer and epoxy resin and to biocomposites with natural fibers, particularly cellulosic fibers, as reinforcements. The primary advantage of this invention over previous approaches are that the polyglycoside polymers are environmentally friendly and cost effective. The polymer matrix for this invention is preferably composed of 50 wt % by weight of glucose based copolymer and 50% by weight of epoxy resin. The glucose based copolymer is a biodegradable. The preferred glucose based copolymer is thus used as a hardener for epoxy resin of the polymer matrix formulation. Hence the polymer matrix formulations do not need any toxic and expensive curing agents that are used to conventional epoxy curing systems.
The cured polymer matrix shows the relatively constant performances in the wide ranges of curing conditions. The curing process of the polymer matrix depends only on the energy that induces the reaction between glucose based copolymer and epoxy resin. Hence a temperature controlled convection oven can be necessary for the even temperature distributions on curing of the samples for the scale up. The poor heat transfer property of the polymer matrix can cause the sticky property of the less cured polymer matrix or volume shrinkage of the over cured polymer matrix if the curing is not controlled. The lamination of the polymer matrix sheets to fillers can be alternative methods for implementation. Alternatively microwave, RE electron beam and UV processing can be used.
The matrix formulation is very stable at room temperature so the pot life is long enough for applying it to the fabrication process. The cured polymer matrix shows thermal stability up to 300xc2x0 C. and maintains the mechanical performance in wet environments. The polymer shows good compatibility with hydrophilic natural fibers, particularly cellulosic fibers, to fabricate biocomposites, making special treatments of hydrophobic polymer matrix or hydrophilic fiber surface to improve the adhesion unnecessary. The markets for this invention can be expected for the transportation, infrastructure and building industries.
The fillers and their properties are shown in Table 1.
The cellulosic fibers are preferred, particularly cellulosic nanofibers (See FIGS. 11 to 13). Exfoliated clays and graphites can also be used as fillers.